What is Negative Temperature and How Does it Work?

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Discussion Overview

The discussion revolves around the concept of negative temperature, its implications, and the theoretical limits of reaching absolute zero (0 Kelvin). Participants explore the relationship between temperature, thermodynamics, and quantum mechanics, as well as the behavior of systems at negative temperatures.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • Some participants assert that reaching 0 Kelvin is impossible, citing the third law of thermodynamics, which states that one can only approach absolute zero asymptotically.
  • Others argue that to cool a system to 0K, one would need a system at a temperature below zero, which raises questions about the feasibility of such a scenario.
  • One participant introduces a quantum mechanics perspective, suggesting that knowing the momentum of particles at 0K implies uncertainty in their position, complicating the notion of reaching absolute zero.
  • A participant discusses the behavior of objects at different temperatures, proposing that objects at lower temperatures absorb heat more readily, and introduces the idea that a zero temperature object would absorb infinite heat in a short time.
  • Another participant explains that negative temperature is not a contradiction, describing systems that become "cooler" when heated, indicating a willingness to absorb energy from other objects.

Areas of Agreement / Disagreement

Participants generally agree that reaching 0 Kelvin is not possible, but multiple competing views exist regarding the implications of negative temperature and the mechanics behind it. The discussion remains unresolved with differing interpretations of quantum mechanics and thermodynamic principles.

Contextual Notes

The discussion includes assumptions about the definitions of temperature and the behavior of systems at extreme conditions, which may not be universally accepted. There are also unresolved mathematical implications regarding heat absorption at 0K.

hagopbul
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so is it impossible to Reich the 0 Kelvin or not
 
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3rd law of thermodynamics says yes. You can only get asymptotically close.
 
You would need something below zero to cool your system up to 0K. But 0K is the lowest temperature possible. So there are no means you can use to get to 0K.
 
According to QM the answer is no, because if the momentum of all the particles is known to be 0 then you have no knowlage of the position of the particles - but if you know where they are then there's always some uncertainty in their momentum.
 
Fix an object at temperature x. Now, if I have several other objects of lower temperatures [tex]y_1,y_2,...,y_n[/tex]. What do these y values represent?

The answer is that the objects with the smaller y values will absorb more heat in a given amount of time. The problem of course with a zero temperature object is that it would absorb infinite heat in an arbitrarily short time i.e. for any objects x, y and any amount of wattage there are temperatures the objects could have could have so as to exchange energy at that rate.

Negative temperature is not a contradiction, these are systems that become "cooler" when you heat them up, that is they become more willing to receive energy at from another object of given temperature.
 

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